To determine the chemical formula for the compound formed between magnesium (Mg) and nitrogen (N) using Lewis theory, let's go through the following steps:
1. Understanding Valence Electrons and Ion Formation:
- Magnesium (Mg) is in Group 2 of the periodic table and has 2 valence electrons. Magnesium tends to lose these 2 valence electrons to achieve a stable electron configuration, forming a \( \text{Mg}^{2+} \) ion.
- Nitrogen (N) is in Group 15 of the periodic table and has 5 valence electrons. Nitrogen tends to gain 3 more electrons to achieve a stable electron configuration, forming a \( \text{N}^{3-} \) ion.
2. Balancing the Charges:
- When magnesium loses 2 electrons, it forms \( \text{Mg}^{2+} \), having a +2 charge.
- When nitrogen gains 3 electrons, it forms \( \text{N}^{3-} \), having a -3 charge.
3. Combining Ions to Balance Charges:
- To combine these ions to form a neutral compound, we need to balance the total positive and total negative charges.
- The least common multiple (LCM) of the charges +2 (from \( \text{Mg}^{2+} \)) and -3 (from \( \text{N}^{3-} \)) is 6.
4. Determining the Number of Ions Needed:
- To get a total positive charge of +6, we need 3 \( \text{Mg}^{2+} \) ions because \( 3 \times +2 = +6 \).
- To get a total negative charge of -6, we need 2 \( \text{N}^{3-} \) ions because \( 2 \times -3 = -6 \).
5. Writing the Chemical Formula:
- By combining 3 \( \text{Mg}^{2+} \) ions and 2 \( \text{N}^{3-} \) ions, the charges balance out to form a neutral compound.
- The chemical formula reflecting this combination is \( \text{Mg}_3\text{N}_2 \).
Based on this step-by-step analysis, the correct chemical formula for the compound formed between magnesium and nitrogen is \( \text{Mg}_3\text{N}_2 \).
Therefore, the answer is:
[tex]\( \boxed{\text{Mg}_3\text{N}_2} \)[/tex]
